Question 1.Question : (TCO1) Multipath occurs in a radio channel creating small-scale fading due to the following factor: Rapid changes in signal strength Random frequency modulation Time dispersion All of the above None of the above Question 2.Question :(TCO 1) Wavelength is ________________ proportional to frequency. directly inversely not equally 3.Question :(TCO 1) A vehicle is traveling at 25 m/s directly toward the transmitter while receiving a mobile signal at 1900 MHz. What is the received frequency? 1900.00158 MHz 1900 MHz 1899.99842 MHz 1900.000158 MHz None of the above 4.Question :(TCO 1) The coherence bandwidth of a communication channel is estimated to be 2 kHz. Small scale propagation measurements are made in real time from a vehicle moving at 70 m/s. Assuming that samples are taken at intervals of 1/4 the Coherence time to ensure correlation of consecutive samples, how many samples are taken over a 20 m travel distance? 1600 800 3200 2400 None of the above Page: 1 2 Question 1.Question : (TCO1) Multipath occurs in a radio channel creating small-scale fading due to the following factor: Rapid changes in signal strength Random frequency modulation Time dispersion All of the above None of the above Question 2.Question :(TCO 1) Wavelength is ________________ proportional to frequency. directly inversely not equally Question 3.Question :(TCO 1) A vehicle is traveling at 25 m/s directly toward the transmitter while receiving a mobile signal at 1900 MHz. What is the received frequency? 1900.00158 MHz 1900 MHz 1899.99842 MHz 1900.000158 MHz None of the above Question 4.Question :(TCO 1) The coherence bandwidth of a communication channel is estimated to be 2 kHz. Small scale propagation measurements are made in real time from a vehicle moving at 70 m/s. Assuming that samples are taken at intervals of 1/4 the Coherence time to ensure correlation of consecutive samples, how many samples are taken over a 20 m travel distance? 1600 800 3200 2400 None of the aboveQuestion 5.Question :(TCO 1) Assume a discrete channel impulse response is used to model an urban RF radio channel with excess delays as large as 125µs.If the number of multipath bins is fixed at 64, what is the maximum RF bandwidth which the model can accurately represent? 2.048 MHz 1.024 MHz 4.096 MHz 512 kHz None of the above 6.Question :(TCO 1) A spread spectrum system using sliding correlation has the following properties: Chip Rate = 32 Mbps; Slide factor 10-4; 24 shift registers in the sequence generator. What is the time between maximum correlations (ÎT)? 68.3µs 57.6µs 25.4µs 46.5µs None of the above 7.Question :(TCO 1) In small scale fading based on Doppler spread, fast fading has the characteristics of: Low Doppler spread Coherence time less than symbol period Channel variations slower than baseband signal variations Both b and c None of the above Question 8.Question :(TCO 2) _________________ diversity can be created without using additional bandwidth. Frequency Time Spatial all of the above None of the above Question 9.Question :(TCO 2) A certain transmission channel has a bandwidth of 2 MHz. What is the channel capacity if the SNR is 37 dB? 12.3 Mbps 18.6 Mbps 24.58 Mbps 36.3 Mbps None of the above Question 10.Question :(TCO 2) Multiple input, multiple output (MIMO) diversity gains can be obtained with the following: multiple receive antennas multiple transmit antennas both a and b neither a nor b Question 11.Question :(TCO 3) What is the bandwidth of a raised cosine filter pulse with a symbol time of 64µs and a roll-off factor of 0.25? 19.5 kHz 80 MHz 26.4 kHz 19.5 MHz None of the above Question 12.Question :(TCO 3) Linear predictive coders (LPC) belong to the ____________ domain class of vocoders. frequency spatial hybrid time None of the above Question 13.Question :(TCO 3) A frequency hopping spread spectrum system has a spread spectrum bandwidth of 2.1 MHz and each hop bandwidth is 7 kHz. How many frequency hop slots are there in this system? 21 15 250 300 None of the above Question 14.Question :(TCO 3) What is the processing gain (in dB) of a spread spectrum system that has system bandwidth of 400 MHz and an information bandwidth of 200 KHz? 33 dB 27 dB -33 dB -27 dB None of the above Question 15.Question :(TCO 3) PN sequences in a spread spectrum communication system ______________ repeat after the period of the sequence is generated. never occasionally always annually Question 16.Question :(TCO 3) A correlation function equals _______________ if the two codes have nothing in common. one 64 zero None of the above Question 17.Question :(TCO 3) Frequency division duplexing (FDD) provides __________ distinct bands of frequencies for every user. One Three Five Seven None of the above Question 18.Question :(TCO 3) A TDMA system has a 25 MHz bandwidth with single channels of 250 kHz bandwidth each, with each frequency channel containing eight TDMA conversation channels. If each user is assigned one transmit and one receive slot within each frequency channel, calculate the number of users this system can support. Assume there is no separate guard band. 100 800 400 200 None of the above Question 19.Question :(TCO 3) A system has eight trailing bits, eight guard bits, 32 synchronizing bits, and three traffic bursts of 64 bits of data per time slot. What is the frame efficiency if there are eight time slots per bit frame? 20% 40% 60% 80% None of the above Question 20.Question :(TCO 4) In a cellular system, channels are reused within _________________. same cell same cluster coverage area Never Question 21.Question :(TCO 4) One of the differences between 2G Mobile Radio Networks and 2.5G Mobile Radio Networks is: Internet browsing is not supported in 2G systems Different transmit frequencies are used Different multiple access technologies are used All of the above None of the above Question 22.Question :(TCO 4) CDMA systems increase a user’s data throughput by _____________________ assigning more frequencies increasing spatial separation between users increasing the length of a PN code allowing the use of multiple Walsh codes None of the above
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